Building Systems Integration - Energy and Cost Analysis The Milton Hershey School New Supply Center Justin Bem AE Senior Thesis – Spring 2007 Mechanical Option Penn State University

Project and Building Background Justin Bem – Mechanical Option Owner - The Milton Hershey School Location – The Milton Hershey School Campus, Hershey, PA Project Size - 110,000 square feet Total Cost - $23,500,000 Design-Bid-Build Contract Construction Dates - July 2006 – July 2007

Project and Building Background Justin Bem – Mechanical Option The Supply Center - General Office and Conference Rooms - Kitchen/Food Preparation Center - Bakery - Clothing Store and Alterations Seamstress - Mail Distribution Center - General Building and MHS Campus Storage

Existing Conditions Justin Bem – Mechanical Option Air Side Mechanical System 14 Total Air Handling Units - 10 VAV Units – Serving General Office and Clothing Areas - 4 CAV Units – 100% Outdoor Air Make-Up Units for Kitchen/Bakery - Chilled/Hot Water Coils - Housed in Elevated Mechanical Mezzanine Floor McQuay Custom Air Handling Unit

Existing Conditions Justin Bem – Mechanical Option Existing Chiller Plant (2) 270 ton Water Cooled Centrifugal Chillers - Primary-Secondary Pumping - 45°F Chilled Water Serves AHU Coils and Walk-in Freezer Condenser - Electric Driven Vapor Compression Machines - Housed in 1 st Floor Mechanical Room Trane Centrifugal Chiller Existing Boiler Plant (3) Natural Gas Fired Steam Boilers - Handles All Building HVAC Heating Demands - Meets Domestic Hot Water Heating Demands

Existing Conditions Justin Bem – Mechanical Option Walk-in Freezer Condenser Water Loop Rejected Heat from Condenser to water loop - Removes Additional Heating Load from Kitchen Space - Load Is Met Directly By Chilled Water Plant Via Plate-Frame HX’s - Water Side “Free” Cooling Is Utilized in the Winter for Heat Rejection

The Redesign Outline Mechanical Redesign Justin Bem – Mechanical Option Effect on Structural System and Building Construction Effect on Electrical System

Mechanical System Redesign Objectives Justin Bem – Mechanical Option Goals - Increase Energy Efficiency - Low Life Cycle Cost - Affordable – (Low First Cost or 2-4 Year Payback Period) Integration of Building Systems with HVAC System - Recover Waste Heat - Perform Multiple Functions from One Fuel Source

Justin Bem – Mechanical Option Dedicated Outdoor Air Systems at The Supply Center -10 Existing VAV Air Handling Units Replaced with 2 DOAS Units - Saves in First Cost - Saves in Fan and Chiller Energy Mechanical System Redesign DOAS/ Water Source Heat Pumps Water Source Heat Pumps at The Supply Center - Water Source Loop Integrates Other Building Systems --Condenser Water Loop Heat Recovery - Gives Ability to Heat and Cool Simultaneously

Justin Bem – Mechanical Option Mechanical System Redesign DOAS/ Water Source Heat Pumps

Justin Bem – Mechanical Option Walk-in Freezers Reject Heat to a Condenser Water Loop - Must Be Cooled for Continues Operation of Freezers - Potential for a Large Amount of Energy Recovery Mechanical System Redesign Condenser Loop Heat Recovery 135gpm Flow Rate 84°F Hot Temperature 65°F Operating Temperature 1282 MBH of Possible Heat Recovery

Justin Bem – Mechanical Option Heat Recovery In Water Source Loop - Water Source Heat Pump Loop Requires Winter Time Heat Addition - Operating Temperature of 68°F - Condenser Water Loop Serves as Heat Source Via Heat Exchanger Mechanical System Redesign Condenser Loop Heat Recovery

Justin Bem – Mechanical Option Heat Recovery In Domestic Hot Water Pre-Heat - High Domestic Hot Water Demand at The Supply Center - Condenser Loop Pre-Heats Water to 76-81°F (Saves 35% Heating Energy) Mechanical System Redesign Condenser Loop Heat Recovery

Justin Bem – Mechanical Option Direct Natural Gas Fired Absorption Chiller-Heaters - Utilizes Natural Gas Service at The Supply Center - Typical Double Effect LiBr/Water Absorption Cycle - Includes Heat Exchanger in High Temperature Generator for Simultaneous Cooling and Hot Water Production (Up to 210°F) Mechanical System Redesign Absorption Chiller-Heater Technology

Justin Bem – Mechanical Option Direct Natural Gas Fired Absorption Chiller-Heaters - Simultaneous Heating Comes at the Expense of Cooling Production - Chiller-Heater Must Run at 30% Cooling Capacity Minimum Mechanical System Redesign Absorption Chiller-Heater Technology

Justin Bem – Mechanical Option Existing System Chiller Plant Load Profile

Justin Bem – Mechanical Option Chiller-Heater Selection - Sized to Meet Cooling and HVAC/Domestic Hot Water Needs - (2) 240 ton Chiller-Heaters Used - Meets Cooling Load with Enough Capacity to Produce Hot Water Mechanical System Redesign Redesigned Chiller/Boiler Plants

Justin Bem – Mechanical Option Redundancy and Reliability -If one Chiller-Heater Is Off Line, Second Meets Critical Load -- Walk-in Freezer’s Condenser System 106 tons -- All other cooling loads are not critical Mechanical System Redesign Redesigned Chiller/Boiler Plants -Back-up Boiler to Meet Heating Demand -- HVAC and Domestic Hot Water INTEGRATES HEATING, COOLING, CONDENSER WATER, AND DOMESTIC WATER SYSTEMS!

Justin Bem – Mechanical Option Mechanical System Redesign Redesigned Chiller/Boiler Plants

Justin Bem – Mechanical Option Energy Rates Mechanical System Redesign Life Cycle Cost Analysis WinterSpring/FallSummer $/Therm Natural Gas Electricity Rates $0.06 / kW-hr

Justin Bem – Mechanical Option Annual Operating Cost Comparison Mechanical System Redesign Life Cycle Cost Analysis $42,800 Annual Cost Savings!

Justin Bem – Mechanical Option Annual Energy Consumption Mechanical System Redesign Life Cycle Cost Analysis

Justin Bem – Mechanical Option Initial Cost Comparison Mechanical System Redesign Life Cycle Cost Analysis $60,000 More Expensive

Justin Bem – Mechanical Option 20 Year Life Cycle Cost Comparison, 6% Interest Mechanical System Redesign Life Cycle Cost Analysis $376,600 Savings Over 20 Years! Existing SystemRedesign System Redesign O&M Costs additional $3,000 more per year

Justin Bem – Mechanical Option Mechanical Redesign Conclusions - Integrates Multiple Building Systems - More Expensive Up Front - Cheaper to Operate - Least Expensive 20 Year Life Cycle Cost Payback In Just Under 2 Years! Mechanical System Redesign Life Cycle Cost Analysis

Justin Bem – Mechanical Option Effect on Structural System and Building Construction

Justin Bem – Mechanical Option Structural/Construction Breadth AHU Relocation Existing System 14 Total AHUs housed in Mezzanine Floor 10 VAV4 CAV Redesigned System 6 Total AHUs 2 DOAS4 CAV Creates Wasted Space in Mezzanine Floor Move AHUs to Roof - Creates Structural Work - Potential to Save Initial Cost

Justin Bem – Mechanical Option Steel K-Series Joist are Replaced with W-flanged Beams Structural/Construction Breadth AHU Relocation

Justin Bem – Mechanical Option No Need to Construct Mezzanine Floor Only Held Air Handling Units Structural/Construction Breadth Mezzanine Floor Cost

Justin Bem – Mechanical Option Large First Cost Savings for Not Construction Mezzanine Floor Structural/Construction Breadth Mezzanine Floor Cost

Justin Bem – Mechanical Option Effect on Electrical System

Justin Bem – Mechanical Option Less Electric Driven Mechanical Equipment - Chillers, 8 AHUs, Boiler Accessories - Changes Load on Distribution Panels - Saves Cost on Feeder and Wire Sizes Electrical Breadth Power System Alterations

Justin Bem – Mechanical Option Electrical Breadth Power System Alterations Additional Electrical Cost

Justin Bem – Mechanical Option Electrical Breadth Power System Alterations Electrical Cost Savings$9,189 New Equipment Electrical Cost$5,534 Total Electrical Cost Savings$3,600 Electrical Cost Savings Mechanical Redesign Creates Electrical Cost Savings!

Justin Bem – Mechanical Option Overall Building System Redesign Cost Analysis Conclusions and Recommendations Final Cost Analysis Existing SystemRedesign Mechanical 1 st Cost$622,840$682,885 Mezzanine Cost$154,458N/A Additional Structural CostN/A$277 Additional Electrical Cost$3,600N/A Total 1 st Cost$780,898$683,173

Justin Bem – Mechanical Option Conclusions Compared to Existing System - Mechanical Redesign Saves Energy and Cost Over 20 Years - Integrates Other Building Systems - Creates Overall First Cost Savings! $ 98,000 Initial Cost Savings $ 42,800 Yearly Cost Savings $ 531,000 Saved Over 20 Years! Redesign Is Beneficial Conclusions and Recommendations Final Cost Analysis

Justin Bem – Mechanical Option Thank You! AE Department - Advisor Dr. Bahnfleth H.F. Lenz Company - Tom Hovan, P.E. Deckman Company - Scott Adams My Great Friends for Their Support! Acknowledgments

Justin Bem – Mechanical Option Building Systems Integration The Milton Hershey School Supply Center Questions?

Justin Bem – Mechanical Option Plant Load Analysis - Walk-in Freezer’s Heat Rejection Creates 106 ton Base Load - Peak Cooling Load at 390 tons -High Hot Domestic Hot Water Demand -- Excellent Opportunity for Simultaneous Heating and Cooling! Mechanical System Redesign Redesigned Chiller/Boiler Plants

Justin Bem – Mechanical Option Mechanical System Redesign Redesigned Chiller/Boiler Plants AHUOutdoor Air Supplied Total23,445 DOAS DOAS Total9,791 Difference13,654

Justin Bem – Mechanical Option Existing System Chiller Plant Load Profile

Justin Bem – Mechanical Option Existing System Chiller Plant Load Profile

Justin Bem – Mechanical Option New System Chiller Plant Load Profile

Justin Bem – Mechanical Option AHU Relocation - Beams sized to limit deflection to avoid ponding Δ = 5wl 4 /(384EI) Δ = L/240

Justin Bem – Mechanical Option Additional Cost of Redesign Is Small! Structural/Construction Breadth AHU Relocation